Lets say I have some rest api where arguments are time when to execute method and second argument is name of the method in class. What is the best way for invoking call of this method in certain time (just once) in spring-boot application ?
First, enable scheduling in your spring-boot application:
#SpringBootApplication
#EnableScheduling
public class Application {
// ...
Then, inject the TaskScheduler bean and schedule the task programmatically every time the user invokes the REST method:
public class MyScheduler {
#Autowired
private TaskScheduler scheduler;
public void scheduleNewCall(Date dateTime) {
scheduler.schedule(this::scheduledMethod, dateTime);
}
public void scheduledMethod() {
// method that you wish to run
}
}
However, you should also think about limiting the amount of calls to this method, otherwise the malicious user could schedule a lot of tasks and overflow the task pool.
I have an Spring Boot application in which I have a class with two methods likes below.
#Component
public class ClassA {
#Scheduled(fixedDelay = 900000)
public void methodA(){
//do task "A"
}
#Scheduled(fixedDelay = 600000)
public void methodB(){
//do task "B"
}
}
As per my understanding methodA should execute every 15 minutes and methodB should execute every 10 minutes. But as soon as applications starts both the jobs get invoked. Is this the right behavior ? If yes, then how can I stop them from execution immediately after application startup and run methodB after methodA?
As form the documentation: Scheduled (Spring Framework 5.0.4.RELEASE API)
fixedDelay: Execute the annotated method with a fixed period in
milliseconds between the end of the last invocation and the start of
the next.
What you want is
initialDelay:
Number of milliseconds to delay before the first
execution of a fixedRate() or fixedDelay() task.
I am in a service, with a scheduled task, and I want to get an object from the database. It has EAGER associations, so the find method should get it totally.
#Service
public class CustomTask {
#Autowired
CustomRepository customRepository;
#Scheduled(fixedRate = 1000)
public void action() {
customRepository.find(1);
}
}
But here it doesn't work. The associations are null.
While inside a Spring Boot Controller, the repository method works perfectly.
Do you know I can get my whole object in this Scheduled method of a Service?
The scheduled task is called at the beginning of the app, at a moment where the environment may not be totally initialized.
With an initial delay to the task, I can access my whole object :
#Scheduled(initialDelay=10000, fixedRate = 1000)
NB : It is more a workaround than a fix.
I have a #Scheduled task in my application which is setup using CRON and run every 4 hours. The problem I face is that the CRON job does not start immediately after application startup but it starts only 4 hours after the application startup.
I tried to use a #PostConstruct method inside the task to invoke it, but that results in an error due to an uninitialized Spring context.
Please tell me how I can make the Scheduled task run immediately on application deployment and then on every 4 hours after the deployment.
EDIT:
I would not use a #PostConstruct since my scheduled method depends on other Beans , which are not initialized when this PostConstruct method runs for some reason.
By 0 */4 * * * you specify "At minute 0 past every 4th hour (0:00, 4:00, 8:00 etc.)", which is not at startup time and then every 4 hours as I think you want.
You can specify initial delay and rate by:
#Scheduled(initialDelay=0, fixedRate=4*60*60*1000)
If you are worried about hard-coded values, you can still provide config value:
#Scheduled(initialDelay=0, fixedRateString = "${some.config.string}")
I had #EnableScheduling in my app config. I had
#Scheduled(fixedDelay=5000) in my scheduled task class. Even then it didn't work.
I added #Service to my scheduled task class and everything worked fine.
I was having the same situation. I need to run cron scheduler every 1st day of the month and also when the application starts.
This is how I achieved using ApplicationListener.
import org.springframework.context.ApplicationListener;
import org.springframework.boot.context.event.ApplicationReadyEvent;
#Component
public class ApplicationReadyListner implements ApplicationListener<ApplicationReadyEvent> {
#Override
public void onApplicationEvent(ApplicationReadyEvent event) {
// callYourTask();
}
}
I'm not sure if you have tried this but you can use #Scheduled with an initialDelay
For fixed-delay and fixed-rate tasks, an initial delay may be specified indicating the number of milliseconds to wait before the first execution of the method.
https://docs.spring.io/spring/docs/current/spring-framework-reference/html/scheduling.html#scheduling-annotation-support-scheduled
#Scheduled(initialDelay=0, fixedRate=5000)
public void doSomething() {
// something that should execute periodically
}
I assume this will execute your scheduled method when the application is run.
If is not possible to use initialDelay attribute with the cron rule and your intention is execute this Job after every restart, you can implement a CommandLineRunner on your application class:
#SpringBootApplication
public class MyApplication implements CommandLineRunner {
public static void main(String[] args) {
SpringApplication.run(MyApplication.class, args);
}
#Autowired
private TaskService taskService;
#Override
public void run(final String... args) throws Exception {
taskService.run();
}
}
It's not the best strategy, but works.
Just specify the method you want to run in the init_method attribute of the bean.
Java config: #Bean(init_method="methodWhichStartsTask")
XML config: <bean id="someId" class="com.example.Clazz" init-method="methodWhichStartsTask"/>
This will invoke the method just after the bean is properly initialized and if the method is scheduled, then it will be called afterwards every 4 hours.
Instead of cron inside #Scheduled, use fixedRate like below. By default initialDelay is -1, which will start immediately or you can set 0.
#Scheduled(fixedRate=4*60*60*1000)
public void test() {
System.out.println("helloworld");
}
user #EnableScheduling annotation on your class which contains you1 scheduled method:
see spring document:
To enable support for #Scheduled and #Async annotations add
#EnableScheduling and #EnableAsync to one of your #Configuration
classes:
#Configuration
#EnableAsync
#EnableScheduling
public class AppConfig {
}
link : https://docs.spring.io/spring/docs/current/spring-framework-reference/html/scheduling.html
#EnableScheduling annotation should be added in the main class for the Spring application.
Example :
#SpringBootApplication
#EnableScheduling
public class MyApplication {
public static void main(String[] args) {
SpringApplication.run(MyApplication.class, args);
}
}
and above the method where the actual scheduling needed we need to add
#Scheduled(initialDelay = 1000, fixedDelay = 4*60*60*1000)
Example:
#Scheduled(initialDelay = 1000, fixedDelay = 4*60*60*1000)
public void schleduleWork() {
/* Code Here */
}
For the above scheduler the first hit will be at 1000 milli second and subsequest hits will be at the interval of 4 hrs
Got a pretty standard Spring Boot (1.3.5) application.
Enabled scheduling with #EnableScheduling (tried on main application entry point and a #Configuration annotated class.
Created a simple class with a #Scheduled method (simple fixedDelay schedule).
Scheduled task executes twice (always).
From what I have gathered so far, it is probably because two contexts are being loaded, and thusly picking up my beans twice.
Ok.
So how do I fix/prevent this double execution, since all the config is basically hidden Spring Boot magic?
Framework versions:
Spring Boot 1.3.5
Spring Cloud Brixton SR1
Main application:
#SpringBootApplication
#EnableDiscoveryClient
#EnableAsync
#EnableCircuitBreaker
public class AlertsApplication {
public static void main(final String[] args) {
SpringApplication.run(AlertsApplication.class, args);
}
}
My task class (HookCreateRequest list is pulled in from application.yml - I do not believe that to be relevant currently, but if required, can be provided):
#ConditionalOnProperty(name = "init.runner", havingValue = "InitRunner")
#ConfigurationProperties(prefix = "webhook")
public class InitRunner /*implements CommandLineRunner*/ {
private final List<HookCreateRequest> receivers = new ArrayList<>();
#Autowired
private WebHookService hookService;
#Scheduled (fixedRate = 300000)
public void run() throws Exception {
getReceivers().stream().forEach(item -> {
log.debug("Request : {}", item);
hookService.create(item);
});
}
public List<HookCreateRequest> getReceivers() {
return receivers;
}
}
There is zero xml configuration.
Not sure what else might be relevant?
EDIT 2016/07/04
I have modified to output the scheduled instance when it runs (I suspected that two different instances were being created). However, the logs seem to indicate it is the SAME instance of the task object.
logs:
15:01:16.170 DEBUG - scheduled.ScheduleHookRecreation - Schedule task running: scheduled.ScheduleHookRecreation#705a651b
...task stuff happening
...first run completes, then:
15:01:39.050 DEBUG - scheduled.ScheduleHookRecreation - Schedule task running: scheduled.ScheduleHookRecreation#705a651b
So it would seem it is the same task instance (#705a651b). Now why would in the name of sweet things would it be executed twice?
EDIT 2016/07/05
I added a #PostConstruct method to the class that carries the scheduled method, with just some logging output in. By doing that I could verify that the #PostConstruct method is being called twice - which seems to confirm that the bean is being picked up twice, which which presumably means it is fed to the scheduler twice. So how to prevent this?
Had the same problem, in my case the reason was in #Scheduled annotation's initialDelay parameter absence - method was called on application start.